Pneumatic spring suitable for vehicles



Sept 20, l932- c. w. CALDWELL L8735 PNEUMATIC SPRING SUITABLE FOR VEHICLES Filed July l2, 1928 Patented Sept. 20, 1932 CHARLES WILLIAM` CALDWELL, or JoHANnEsBURe, TRANsvAAnnNAIoN or sourir Y AFRICA y PNEUMATIC SPRING sUrTAnLn ynon. vnnrCLns Application filed July 12,

` rIhe present invention relates to pneumatic spring devices suitable for thel suspension of motor car bodies, cycle saddles, cycle 'frames and for similar uses. The object of theinvention is to provide aspring which oiers resista-nce commensurate with the intensity of the shocksy imposed upon it and which checks the rebound movement.

The invention is illustrated in the accompanying drawing in which l Fig. I is a vertical section of one formi of the invention.

Fig. II is a'sectional View of Fig. II-II Fig. I, sho-wing Va. valve.4 n

Fig. III` shows Vanother i'orm'of valve. Fig. IV shows another form of spring'to a smaller scale.

2 indicatesthe body oi a vehicle and B'the axle from which the body is supported by means of the pneumatic spring. Y

l The spring comprises twoV bellows L1, 5,1 so connected together that when either is coinpressed thefother is expanded. For this purpose they are shown secured to opposite 'faces of a common intermediate plate-6 and having their end plates 7, 8 rigidly connected by I on bolts 9.The interior spaces ofthe two bel-V lows are put in communication with one,

another by, for instance, an aperture 10 in the intermediate plate 6. The bellows are charged with compressed air through a valve 11, so that both resist compression. The'area of the end 7a of the bellows et' is greater than that oi the end 8a of the bellows 5, so that the bellows l 'Oilers a greater resistance to coiniression" than the other bellows 5 and said.

bellows l is arranged to sustain the weight of the body.V For this `purpose in the I.

arran ement the bod 2 is rixuuite'dv b*- brackets 12 engaginglugs 13 on said plate 6;

and the lower end plate? is supported by the axle 8. Fig. IV reverses this arrangement; the plate@ being supported on the axle 3 witl the bellows positioned` above the bellows 5;

i and the body 2 secured .to the end plate?.

"Upward movement of the axle 3 relatively to the body 2 causes tobe displaced from the bellows 4' into the bellows 5, and the volume occupied by the air being thereby decreased,its resistanceto the displacement in- 192s.` seriai No. 292,130.

rebound of the bodybeyond its normlalposi-Y tion relatively to the axle.

14C' represents a valve for regulating the area of the aperture 10 and therefore .its throttling eiiect.

sliding in the'slot and having upper and lower fianges '15 whiohjextend beyond the block at the' sides and'end for coveringlthe aperture 10.'V They valve is adjusted to cover more or less of the aperture. 10; and in the Fig. III formthis is done by means-o1c a rotatable spindle` 16 extending through the plate 6 andhaving a'threaded end 17'screwed into the block 14. The external end 18 of the The aperture is in they form of a slot; the' valve-comprising-a block" spindle is squared to receive a wrench; and a st'uiingfbox :19 is provided topreventthe escape of air. f .j

In the construction of Figs. I and II Vthe valve openingV is arranged to vary-autoinati-V cally according to the rate of iiow of air past it. VrIhe valve is provided with a spring 2O tending to move it to close the aperture 10.

The end of the valve which limits thev aper-Y ture 10 is bevelled to 'providethe surfaces 21 inclinedaway romthe aperture. Air flow- 'ing through the apertureimpinges on one of the inclined'V surfaces and forces the valve open to anfextent varying with Vthe velocity of they flow. 221s a' set screw for limiting the closing movement of the, valve, screwed through. the plate@ and iitted with a stuihng box 23. V211 is a similarly arranged screw which bears against theoback of the spring 20. By retracting this screw the pressure of the spring on the valve diminishedand the valve is allowed to open more for -a given velocity of flow through the aperture 10. Y indicates an'air storagel reservoir with which the bellows may be put into communication by means of a pipe 26'controlled by a valve 27. Said reservoir `has the eect of increasing the volumetric capacity of the bellows and so decreasing the ratio of resistance to compressive movement.

g5' another, the intermediate plate and the outer end vassembly forming the mechanical ends of the spring,1one of said springs offering a greater resistance'than'the other and forming the weight sustaining memb-er of the 30 combination. Y Y a 2. A pneumatic .device comprising two pneumatic springs requiring different forcesV to compress'them equally and 'connectedby Y means providing forthecompression of one` i spring-simultaneously with extension of the other spring, means connecting the air bodiesV in the springs, a valvecontrolling the flow from one'air body to the other,^a spring tend-V ing to close said valve, said valve having a Vmf; surface exposedto'air flowing from one air body to the other and so inclined that the re- Y action of the flowing f to open the valve. t Y

. 3. A pneumatic device comprising two pneumatic springs requiring different forces Y to compress them equally andconnected by means providing for the compression of one spring simultaneously with extension of the other spring, means connecting the air bodies 5min the' springs, a valve controlling the flow from one air body to the other, a spring tending to close said valve, said valve having a surfaceexposed to air flowing from one air body to the other and so inclined that theV reactionof ythe flowing air i on lsaid surface tends to open the valve, and means to adjust the ratio of the forces exerted on the valve respectively by the spring and the flowingA air.V

A 4.v A pneumatic device comprising Atwo pneumatic springs requiring different forces to compress them equally and connected by means providing for the compression of one spring simultaneously with extension ofthe other'spring, means connecting the air bodies in the-springs, a valve controlling the flow Itis preferred to'make the bellows of varying cross sectional area as shown. The smallair on said surface tends from one air body to the other, a spring tendving to close said valve, said valvehaving a surfaceexposed to air flowing from one air body to the `other and so inclined 'that the reaction of the flowing air on said surface tends to open the-valve, and an adjustable stop to regulate the closing movement Vof the valve.

5. A spring device suitable for vehiclev suspension comprising an intermediate plate, two pneumatic springs arranged at opposite sides of .said plate, `said plate being perfoiatedto put'the springs in communication with one another, the outer end of the springs,Y being rigidly connectedto one another, the intermediate plate and the outer end assembly forming the mechanical ends ofthe spring, one of saidsprings offering aA v.greater resistance than the other and forming the weight 'sustaining member of the combination. 1

6,. A spring device suitable for vehicle suslpension comprising an intermediate plate,

two bellows springs arranged at opposite sides of said plate and with their air bodies in permanent communication with one another, each bellows comprising an end plateand said end plates being rigidlysecured to one another, the end plate assembly and the intermediate plate forming the mechanical ends'ofthe spring.-

7. A spring device suitable for vehicle suspension comprising van intermediate rigid structure, two bellows springs secured to the opposite sides of said intermediate structure,

each of said springs comprising a plurality of bellows unitsV which differv successively from one another in diameter so that each spring is of tapering-form lengthwisefthe outerV ends ofthe springs being rigidly con-f nected to one another, the intermediate strucmechanical ends of the spring, oneof said springs offering a greater resistance to compression than the other, andmeans placing the air bodies of Vsaid springs in communication with one another. y i 8. .A springdevice suitable for vehiclesuspension comprisingV an intermediate rigid structure, twobellows springs secured to the ing the air bodies of said springs in throttled communication with one another.

Inv testimony whereof I afixmy signature.

CHARLES' WILLIAM CALDWELL."`

esl

-ture and the outer end assembly forming the. n

opposite sides of said intermediate structureA v 

